This renewal application for the Pediatric AIDS Clinical Trials Unit at the University of Miami School of Medicine (Miami PACTU) proposes the conduct of clinical trials in pregnant women, infants, children and mouth with HIV infection. We propose to enroll at least 69 patients yearly into various protocols with special emphasis on the areas of prevention of perinatal transmission, antiretroviral therapy in pediatric nd adolescent populations, and the prophylaxis and treatment of opportunistic infections. This program, consisting of a pediatric unit and an obstetric unit, has had a distinguished record in clinical trials over the past three years. Dr. Mary Jo O'Sullivan and Dr. Gwen Scott are part of the PACTG leadership. They are both currently members of the Executive Committee and serve as the obstetric chairperson and pediatric o-chairperson respectively for the Perinatal Transmission Committee. The Miami PACTU has provided scientific input into the design of clinical trials and the development of the scientific agenda of the PACTG. We have participated in the conduct of all phases of clinical trials in both pregnant women and children and have enrolled patients into adolescent protocols. The Miami Perinatal Research Network provides an extensive infrastructure of psychosocial and medical support for the Miami PACTU which has facilitated he enrollment and retention of patients in clinical trials at our site. Over 90% of the patients enrolled into clinical trials are members of minority groups. We have excellent support from both the virology and immunology laboratories who are certified by the ACTG and have participated in multiple past PACTG protocols. bong term goals of this project are consistent with the PACTG agenda and include the reduction of perinatal transmission to less than 2%, a better understanding of the pathogenesis of HIV, delayed disease progression, and prolongation of survival. The strengths of this program lie in the expertise of its faculty, the demonstrated leadership within the clinical trials group, its distinguished record in the conduct of clinical trials, the large patient population, the extensive infrastructure developed in support of clinical trials, and the integration with community programs.